Insights into the mechanism of the reaction between hydrogen sulfide and peroxynitrite

Nitrosopersulfide (SSNO − ) decomposes in the presence of sulfide, cyanide or glutathione to give HSNO/SNO − : consequences for the assumed role in cell signalling

“…Now, we combined 15 N NMR with ESI-TOF-MS data to observe the reaction product of SSNO 2 with sulfide. When acetone solutions of PNP þ SS 15 NO 2 were mixed with Na 2 S and the reaction monitored by 15 N NMR, a clear shift in 15 N NMR from 354 ppm to 314 ppm is noticeable. The NMR (314 ppm) signal was also observed previously in the wavelength (nm) Sulfur precipitated from this reaction, most probably from HS À 2 .…”

“…In addition, when we studied the reaction of H 2 S 2 with NO þ BF 4 , we observed that although the product is SSNO 2 it is not nitrosopersulfide but its isomer, dithionitrate, with distinct UV/Vis, 15 N NMR and IR characteristics and different chemical reactivity [36]. Finally, cyanides are known to react with sulfane sulfur [45]; however, the putative 'SSNO 2 mix' was resistant to the cyanide treatment [35].…”

“…If CN 2 indeed reacted with sulfane sulfur then the reaction products should be SCN 2 and SNO 2 (equation (3.4)). To resolve the product identity, we mixed SS 15 NO 2 with C 14 N 2 and recorded both 14 SS 15 NO À þ C 14 N À ! SC 14 N À þ S 15 NO À ð3:4Þ…”

“…It is now well established that H 2 S strongly interferes with NO signalling, either by reacting directly with NO [12] and its metabolites (S-nitrosothiols (RSNO) [13], peroxynitrite [14,15] and nitrite [16][17][18]) or by modulating NO production [19] and cGMP production [20] and degradation [21,22]. Namely, even the first reports on H 2 S-induced vasodilatory effects showed that endogenous H 2 S functions as a smooth muscle tone regulating factor in synergy with NO [23].…”

Sulfide Homeostasis and Nitroxyl Intersect via Formation of Reactive Sulfur Species in Staphylococcus aureus

“…These RSS are sensed by CstR (29), leading to the upregulation of a sulfide oxidation system that includes a canonical sulfide:quinone oxidoreductase ( SQR ) (26, 81). The RSS can also be derived from exogenous or endogenous NO·, which reacts with oxidized sulfur species (S ox , RS ox ) to create the nitrosothiol thionitrous acid (HSNO) and organic nitrosothiols (RSNO), which in turn react with S 2– to make HNO (82-86). HNO can also be made via 1-electron reduction of NO· or other transformations (top of figure; note that not all possible reactions are shown [85]).…”